One reader from Oxfordshire who did not want to be named said his family had abandoned plans to build their own home and were braced for years of financial struggle.

He said: “We have cancelled plans to buy a plot to build our own house, we are wishing we hadn’t already booked an expensive European holiday, which we had taken out a loan to pay for. And we are uncertain about whether to take out a new fixed rate mortgage on our house now that we are unlikely to be selling it to pay for the build.

“We will be returning to the ‘survival mode’ approach to spending that we took following the banking crash, as we expect years of financial struggle ahead.”

An IT consultant from Dorset, who also did not want to be named, said the company he worked for had cancelled plans to hire 30 new staff and a customer in Germany had postponed a €130m (£108m) contract.

He said that spending on IT was often one of the first things to be cut by companies in times of economic uncertainty, because much of it was discretionary rather than essential.

“Decisions are being postponed. This happened massively during the financial crisis and it’s happening again. We have reduced UK sales forecasts by 15% purely because of Brexit.”

Another Guardian reader from Milton Keynes said that plans to buy a property in Spain had fallen through. “We will probably never be able to afford a property in Spain again,” he said.

Haart said new listings from people selling homes were down by 3.9% last weekend compared with the same weekend a year earlier, while calls into branches were 7% below the trend for the three weeks in the run-up to the vote.

The firm, which has more than 100 branches across England, said that it had seen an increasing number of people booking valuations “to understand what effect there has been”.

Charles Perdios, who runs estate agency Anthony Pepe in north London, said some sales had fallen through since the weekend. “One was a lady who pulled out of a sale because her job was funded by the EU, so she was directly affected by the result,” he said.

“We have had a couple of people saying they’re going to take their houses off the market and wait now.”

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Perdios said on Friday morning there was a flurry of calls from would-be buyers “trying their luck” with offers up to 15% below asking price, although these had not been accepted.

Some other deals had been renegotiated following the decision: “We have negotiated a few down. We are expecting 20% fewer transactions in the second half of the year than we expected before.”

David Hollingworth of mortgage broker London & Country saidborrowers have been pulling out of purchases. “There are some who are quite early on in the process, who haven’t spent money on solicitors or surveys, who do not feel wedded to a property, who have decided to wait and see what happens rather than going ahead,” he said.

Research published by the National Association of Estate Agents (NAEA) showed that before the vote demand for property had already fallen to a three-year low.

Mark Hayward, managing director of the NAEA, said: “Although in the short term, we believe that house prices will remain stable, we cannot be certain about the next quarter as political uncertainty and market unrest could affect the housing market.”

On the parenting forum Mumsnet, people shared concerns about going ahead with house purchases, spending money on extensions, and the sort of reception they might receive when holidaying within the EU.

One prospective home buyer wrote: “From all the data, it looks like we will be buying at what would be a peak. I am getting very nervous now about a crash ... Should we pull out? Please help me to get some perspective here.”

Abta, which represents UK travel agents and tour operators, said it was “too soon to tell” what impact Brexit would have on the industry.

A spokeswoman said: “People due to travel this summer will see little changes to their holiday. However, the fall in value of the pound will have an immediate impact on holidaymakers and their spending power overseas.”

Holiday group Thomas Cook said that it was focused on business as usual. “At this early stage the implications of the UK vote to leave the EU are still unclear,” a spokeswoman said.

She added: “Like other UK-listed companies we will of course be monitoring events very closely over the coming days and months and we will provide updates on any developments as they become clear.”